The object of this study is to evaluate the relationships between human immune response genes, atopic allergy, the HLA linkage group including GBG, PCM3 and the vigor of the immune response to several viral antigens. Ten large ragweed sensitive families will be studied. A careful clinical evaluation of atopic allergy will be carried out on each family member. Then each will be studied regarding the immediate skin test response and quantitation of IgG and IgE antibodies against purified ragweed antigens, HLA antigens, third phosphoglucomutase locus (PGM3), glycine-rich B glycoprotein (GBG), serum immunoglobulins, microtiter viral antibody test for several viruses, mixed lymphocyte cultures, red cell antigens and PHA response of lymphocytes. Viral seronegative subjects will be vaccinated with the particular virus. The ragweed antigens used will be standardized and characterized with regards to purity. The studies will be done before and after intranasal challenge with ragweed. This diagnostic procedure will be done in order to minimize the lack of uniform antigenic exposure. The data will be analyzed by the lod scores method of Morton as modified by Ott and Elston. First we will attempt to find the best genetic model and then to consider the age-dependent genetic penetrance. In addition, since we will determine the GBG and PGM3 polymorphisms, it will be possible to study genetic distances since these markers will permit the definition of recombinants between HLA-B, HLA-D, GBG and PGM3. The analysis of the position of IrE with respect of these loci will now be possible. BIBLIOGRAPHIC REFERENCES: Blumenthal, M., Mendell, N., Yunis, E., Amos, B., Elston, R., "Genetics of Ragweed Allergy", (abstract), to be presented at the American Congress of Allergy and Immunology, March 27 -30, 1977. Dalmasso, A., Blumenthal, M., Emme, L., Noreen, H., Kelly, J., Yunis, E., "HLA Analysis in Hereditary Angiodema", (abstract), to be presented at the American Congress of Allergy and Immunology, March 27 -30, 1977.